TLR2 and mastitis: Differential expression of SYK and related genes in bovine mammary tissues (normal and mastitis tissues) were detected via qRT-PCR and showed that SYK gene expression was significantly down-regulated in mastitis, while AKT1, TLR4, TLR2, IL1β, IL-8, IL-10, NF-κB and NLRP3 gene expression were significantly up-regulated (Supplemental Figure S4).